Ambient Light Sensor Package with Integrated Die Shielding
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Solution Overview
Problem
Ambient light sensors in electronic devices are sensitive to light contamination within the device, requiring external light isolating gaskets for stray light blocking, which complicates the manufacturing and assembly process.
Innovation Solution
The integration of a light shielding layer on the ambient light sensor die and wafer surfaces, forming an opening aligned with the light sensor, and the use of conductive bumps for electrical and mechanical coupling, along with a transparent protective cover to allow ambient light sensing while blocking stray light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a light isolating gasket is placed over the ambient light sensor after installation to block stray light, then light isolation performance is improved, but device complexity and manufacturing complexity increase
Solution Approach 1:
The light shielding layer is integrated directly into the ambient light sensor die structure, merging the light isolation function with the sensor substrate. This eliminates the need for separate light isolating gaskets and reduces the number of assembly steps, thereby reducing manufacturing complexity while maintaining light isolation performance
Solution Approach 2:
The light shielding layer is formed on the ambient light sensor die before the sensor is installed in the device. This preliminary integration of the light shielding function into the die structure allows for simpler subsequent assembly processes and reduces manufacturing complexity
2Object-affected harmful factors
If a light isolating gasket is used to block stray light, then light isolation is improved, but the number of components and assembly steps increase
Solution Approach 1:
The light shielding layer is formed as an integral part of the ambient light sensor die structure, combining the light isolation function with the sensor substrate. This eliminates the need for separate light isolating gasket components, reducing the total number of components while maintaining effective stray light blocking
3Ease of manufacture
If the ambient light sensor is shipped without light isolation material and the gasket is attached later, then shipping and handling are simplified, but assembly complexity increases
Solution Approach 1:
The light shielding layer is formed on the ambient light sensor die before shipping, preliminarily integrating the light isolation function into the die structure. This allows the sensor to be shipped in a ready-to-use state with light isolation already in place, eliminating the need for separate gasket attachment steps at the customer site and reducing assembly complexity
4Difficulty of detecting and measuring
If optical testing is performed after device assembly, then testing is simpler, but light isolation performance cannot be optimized early in manufacturing
Solution Approach 1:
The light shielding layer is formed on the ambient light sensor die before device assembly, allowing optical testing to be performed at an earlier stage in the manufacturing process. This enables light isolation performance to be optimized and verified early, before final device assembly, while still maintaining testing simplicity through standardized procedures
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enhances light isolation, reduces manufacturing complexity, and allows for simpler optical testing before package separation, resulting in more efficient and cost-effective ambient light sensor packages with improved performance.
Implementation Method 1
The light shielding layer is provided on at least the first surface and the second surface of the ambient light sensor die, and defines an opening aligned with the light sensor
Data Source
AI summary
One or more embodiments are directed to ambient light sensor packages, and methods of making ambient light sensor packages. One embodiment is directed to an ambient light sensor package that includes an ambient light sensor die having opposing first and second surfaces, a light sensor on the first surface of the ambient light sensor die, one or more conductive bumps on the second surface of the ambient light sensor die, and a light shielding layer on at least the first surface and the second surface of the ambient light sensor die. The light shielding layer defines an opening over the light sensor. The ambient light sensor package may further include a transparent cover between the first surface of the ambient light sensor die and the light shielding layer, and an adhesive that secures the transparent cover to the ambient light sensor die.